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NOUS41 KWBC 051917 AAB

Technical Implementation Notice 15-36, Amended
National Weather Service Headquarters Washington DC
315 PM EDT Mon Oct 5 2015

To:     Subscribers:
     -Family of Services
     -NOAA Weather Wire Service
     -Emergency Managers Weather Information Network
     Other NWS Partners, Users and Employees

From:  Timothy McClung
      Chief Operating Officer
      NWS Office of Science and Technology Integration

Subject:  Amended: Upgrade to Global-Real Time Ocean Forecast
      System (RTOFS) a date to be determined (TBD)

Amended to change the implementation date from October 6 to TBD

Effective TBD, beginning with the 0000 Coordinated Universal
Time (UTC) run, NCEP will upgrade the Global-RTOFS.

The system changes include:

- An increase in the number of vertical layers from 32 to 41
hybrid layers with additional iso-level coordinate layers in the
upper ~200m.
- The coupling of the ocean component Hybrid Coordinate Ocean
Model (HYCOM) to Los Alamos National Laboratory`s Community Sea
Ice (CICE) model using v4.0 of Earth System Modeling Framework
- Updated bathymetry, which improves representation of grid
points in shallow regions where minimum depth is set to 5m.
- An update of the climatology from the U.S. Navy`s Generalized
Digital Environmental Model (GDEM) v3.0 to v4.2.
- An equation of state, which is updated from 9 terms to
17 terms.

Benefits of the system changes include:

- Fine vertical resolution in the oceanic mixed layer with
9 additional near surface layers.
- Anticipated improvement to air-sea boundary flux for future
coupled applications (including hurricanes).
- Improved vertical coastal ocean resolution for downstream
applications, such as the National Ocean Service Operational
Forecast System (NOS-OFS) and Eco forecasting.
- Planned addition of Sea Ice products.

Product Additions:

- The following NetCDF files will be made available on the NCEP
Sea Surface Temperature (SST) and Surface current components U,
V time series for the last day of nowcast/hindcast
SST and Surface current components U, V time series where "#"
equals day 4 or 5 of forecast

SST and Surface current components U, V time series for days 1-3
of forecast

Where "????" is either "prog" (Prognostic) or "diag"
Where "X" is either "f" (Forecast) or "n" (Nowcast)

- The following surface files will now be available on the NCEP
Where FFF is either hourly "f00"-"f192" or "n00" or hourly "n-
- The following ice files will now be available on the NCEP
Where ??? is either "anal" or "fcst1" or "fcst2"

Details on the contents of these files are available at:

Product Changes:

- The high vertical resolution (hvr) regional NetCDF files will
be renamed on the NCEP server.The file name changes reflect
more descriptive region names.The file name changes are as
follows: --> --> -->

Where "HHH" is from 000-048 --> --> -->

Where "HHH" is from 001-192

- The current 3d archive files will now be available every 6
hours for both forecast and nowcast and the "a" files will
become compressed
 rtofs_glo.t00z.*.archv.a -> rtofs_glo.t00z.*archv.a.tgz

A consistent parallel feed of data will be made available on the
NCEP HTTP server once the model is running in parallel on the
NCEP Weather and Climate Operational Supercomputing System
(WCOSS) on or around July 21.  The data will be available at the
following URL:

No changes are expected to products over NOAAPORT. Users can
find the data via the NCEP ftp and HTTP servers at:

Users can find additional information about the RTOFS at the
following Environmental Modeling Center website:

The original design of the Global RTOFS was that the model would
run throughout the day with all products being available by
00 UTC the following day. With any upgrade it is possible that
delivery times during the day may change either earlier or
later, but the final products will still always be available by
00 UTC the following day.

With this upgrade certain analysis products will be available
earlier, and certain forecast products will be available up to
90 minutes later than current production. NCEP is also removing
the contingency that could have caused the last 2 days of the
forecast to be canceled due to resource constraints. This means
that no part of the Global RTOFS will be pre-emptively canceled.

NCEP encourages all users to ensure their decoders are flexible
and are able to adequately handle changes in content order,
changes in the scaling factor component within the product
definition section (PDS) of the GRIB files, and also any volume
changes which may be forthcoming. These elements may change with
future NCEP model implementations. NCEP will make every attempt
to alert users to these changes prior to any implementations.

For questions regarding the changes to this model, such as
timing, please contact:

   Avichal Mehra
   College Park, Maryland
   Phone: 301-683-3746

For questions regarding the dataflow aspects of these data sets,
please contact:

   NCEP/NCO Dataflow Team
   College Park, Maryland
   Phone:  301-683-0567

NWS National Technical Implementation Notices are online at: is the U.S. government's official web portal to all federal, state and local government web resources and services.